Approximating the Trace Distance Between Product Quantum States

Kun He, Dimitrios Myrisiotis, Junhong Nie +1

We study the trace distance \[D_{\mathrm{tr}}(ρ,σ) =\frac12\|ρ-σ\|_1, ρ=\bigotimes_{i=1}^nρ_i,\quad σ=\bigotimes_{i=1}^nσ_i, \] when the two exponentially large states are specifie…